WCDMA modulation

ABSTRACT

This disclosure describes techniques for modulating data. In one embodiment, these techniques include receiving an I or Q value, generating a time-shifted sample of a shaped pulse based on the I or Q value, and providing the time-shifted sample to a digital-to-analog converter.

RELATED APPLICATION

This application claims priority to U.S. Provisional Patent ApplicationSer. No. 61/173,897 filed Apr. 29, 2009, the disclosure of which isincorporated by reference herein in its entirety.

BACKGROUND

Conventional methods of modulating data for transmission via WidebandCode Division Multiple Access (WCDMA) communications often requireextensive computational logic. This computational logic uses registersthat generate high peak and average current. This peak and averagecurrent may generate radio frequency noise, which causes poortransmission quality and throughput. The radio frequency noise alsotranslates into high development costs associated with correcting suchissues. Furthermore, these registers require a large amount of die area,which can be expensive.

The background description provided herein is for the purpose ofgenerally presenting the context of the disclosure. Work of thepresently named inventors, to the extent the work is described in thisbackground section, as well as aspects of the description that may nototherwise qualify as prior art at the time of filing, are neitherexpressly nor impliedly admitted as prior art against the presentdisclosure.

SUMMARY

This summary is provided to introduce subject matter that is furtherdescribed below in the Detailed Description and Drawings. Accordingly,this Summary should not be considered to describe essential features norused to limit the scope of the claimed subject matter.

In one embodiment, a system is described that includes adigital-to-analog converter, a pulse-shape lookup-table, and an indexedpulse-shape-generator configured to receive an I or Q value, retrieve apulse-shape coefficient from the pulse-shape lookup-table, create atime-shifted sample of a shaped pulse based on the I or Q value and thepulse-shape coefficient, and provide the time-shifted sample to thedigital-to-analog converter.

In another embodiment a method is described that comprises receiving anI or Q value, generating a time-shifted sample of a shaped pulse basedon the I or Q value, and providing the time-shifted sample to adigital-to-analog converter.

BRIEF DESCRIPTION OF THE DRAWINGS

The detailed description is described with reference to the accompanyingfigures. In the figures, the left-most digit of a reference numberidentifies the figure in which the reference number first appears. Theuse of the same reference numbers in different instances in thedescription and the figures indicate similar or identical items.

FIG. 1 illustrates an operating environment configured to reducecomputational logic when modulating data for WCDMA.

FIG. 2 illustrates a Quadrature-PSK constellation.

FIG. 3 illustrates a more-detailed embodiment of part of FIG. 1.

FIG. 4 illustrates a method for modulating data for WCDMA in accordancewith one or more embodiments.

DETAILED DESCRIPTION

FIG. 1 illustrates an operating environment 100 in which techniquesdescribed herein may operate to transform I and Q values into atransmittable signal for use in Wideband Code Division Multiple Access(WCDMA) communications.

Operating environment 100 receives I value 102 and Q value 104 andprocesses these values using modulator 106, converter 108, andtransmission processor 110. By so doing, operating environment 100transforms I and Q values into a transmittable signal.

In the embodiment illustrated in FIG. 1, modulator 106 receives I value102 and Q value 104 at phase corrector 112, which corrects these valuesfor phase and passes the phase-corrected values to gain modifier 114.Gain modifier 114 modifies the gain for these phase-corrected values andpasses each of the gain-modified, phase-corrected values topulse-shape-generator 116 or 118. I indexed, pulse-shape-generator 116time shifts the gain-modified, phase-corrected I value and passes thistime-shifted sample to converter 108. Similarly, Q indexed,pulse-shape-generator 118 time shifts the gain-modified, phase-correctedQ value and passes this time-shifted sample to converter 108.

These time-shifted samples may then be converted into analog signals byconverter 108, here illustrated with I values converted by Idigital-to-analog converter (IDAC) 120 and Q values by Qdigital-to-analog converter (QDAC) 122. Once converted into analogsignals, transmission processor 110 may further process these analogsignals for use in WCDMA communications. To do so, transmissionprocessor 110 includes mixers 124 and 126, a local oscillator (LO) 128,a quadrature circuit 130, and a combiner 132, though other structuresand manners may also or instead by used. These operate to provide atransmittable signal 134.

Ways in which modulator 106 processes I and Q values, as well asoperations of converter 108 and transmission processor 110, aredescribed in greater detail below.

For example, consider a non-limiting, detailed embodiment forillustrative purposes in which I value 102 and Q value 104 are receivedby phase corrector 112 at a rate of 3.84 million I and Q values persecond. Here I value 102 and Q value 104 are the product ofphase-shift-keying (PSK). PSK maps binary data to In-phaseQuadrature-phase (IQ) constellation symbols. An IQ constellation symbolis a plot of an In-phase (I) value along a horizontal axis and aQuadrature-phase (Q) value along a vertical axis.

FIG. 2 illustrates a Quadrature-PSK IQ symbol constellation 200 havingIQ symbols 202, 204, 206, and 208. IQ symbol 202 has a phase offorty-five degrees (shown) and represents binary data of 00, IQ symbol204 has a phase of 135 degrees and represents binary data of 01, IQsymbol 206 has a phase of 225 degrees and represents binary data of 11,and IQ symbol 208 has a phase of 315 degrees and represents binary dataof 10. Note that the I value for a given IQ symbol is the cosine of thesymbol's phase while the Q value of the given IQ symbol is the sine ofthe symbol's phase.

Continuing this detailed example, phase corrector 112 rotates I value102 and Q value 104 by increments of ten degrees in order to correct forphase distortion. The phase distortion is caused by a conventionalanalog power-amplifier (not shown), which induces a phase shift. Phaseshifts for different power amplifications can be calibrated ahead oftime and rotations necessary for correcting each phase shift may bepre-determined and stored. For example, through calibration, it can bepre-determined that a power amplification of X decibels will result in aphase shift of Y degrees. It can then be pre-determined that rotating Ivalue 102 and Q value 104 by Z degrees will correct the phase shift.

To provide still greater detail, consider an example detailed embodimentof modulator 106 illustrated in FIG. 3. Modulator 106 includes one ormore processors 302 and computer-readable media 304, which includesphase corrector 112, gain modifier 114, I indexed-pulse-shape-generator116, and Q indexed-pulse-shape-generator 118. Note however, that this isbut one detailed example; each of these entities of modulator 106 may beimplemented in hardware, software, or a combination thereof.

Phase corrector 112 includes I-and-Q-value buffer 306 andpolar-to-rectangular lookup-table (LUT) 308. Buffer 306 receives I value102 and Q value 104. Polar-to-rectangular LUT 308 includes degrees ofrotation for correcting a phase shift and corresponding correction I andQ values. To minimize the die area used by the table, symmetry isexploited. Polar-to-rectangular LUT 308 includes I and Q values forzero, ten, twenty, thirty, and forty degrees. Phase corrector 112 candetermine I and Q values for all other degrees of rotation by inversionor by swapping I with Q. For example, 320 (−40) degrees has I and Qvalues identical to forty degrees when Q is inverted and 100 degrees hasI and Q values identical to ten degrees when I and Q are swapped and theswapped I is inverted (i.e. for ten degrees I=COS(π/18), Q=SIN(π/18);for 100 degrees I=−SIN(π/18)=COS(10π/18), Q=COS(π/18)=SIN(10π/18)).

Phase corrector 112 determines that a given power amplification willresult in a phase shift and determines a degree of rotation required tocorrect the phase shift. Phase corrector 112 then retrieves correction Iand Q values from polar-to-rectangular LUT 308 that correspond to thedegree of rotation required. Phase corrector 112 uses the correction Iand Q values to rotate I value 102 and Q value 104 by the degree ofrotation. The following is the equation for determining aphase-corrected (rotated) I value:I _(new) =I*A−Q*BThe following is the equation for determining a phase-corrected(rotated) Q value:Q _(new) =Q*A+I*BI represents I value 102, Q represents Q value 104, A represents thecorrection I value, B represents the correction Q value, I_(new)represents the phase-corrected I value, and Q_(new) represents thephase-corrected Q value. In this embodiment, four multiplications andtwo summations are performed for a given rotation. Because thecorrection I and Q values corresponding to the degrees of rotation arecomputed ahead of time, they do not have to be computed at runtime fromthe degrees of rotation. This reduces the amount of computational logicand thus peak and average current are reduced as well as die area usage.

As shown in FIG. 3, gain modifier 114 includes I-and-Q-value buffer 310and Gain lookup-table (LUT) 312. I-and-Q-value buffer 310 receives thephase-corrected I and Q values from phase corrector 112. Gain LUT 312includes all 401 possible gain decibel values (for 0.05 decibelincrements from zero to 20 decibels) in linear form. Thus, starting at afirst index in the table, gain modifier 114 can simply increment to thenext index in order to get the next increment of 0.05 decibels. Becausethe decibel values are in linear form they can immediately be multipliedwith the phase corrected I and Q values to produce phase-correctedgain-modified I and Q values. This requires less computational logic asthe linear equivalent of each decibel value is pre-computed and storedin gain LUT 312.

Continuing this detailed example, I indexed-pulse-shape-generator 116receives the phase-corrected gain-modified I value from gain modifier114 at a rate of 3.84 million values per second. Iindexed-pulse-shape-generator 116 generates a pulse shape for thephase-corrected gain-modified I value and oversamples by a factor of16.25 per value. I indexed-pulse-shape-generator 116 may also implementa timing advance or retardation, which shifts the pulse samples for allnine I values forward or backwards in time by one quarter of a valuetime. A value time is the time between incoming I or Q values. In thisembodiment the value time is one, divided by 3.84 million seconds. EachI value 102 persists for nine value times and thus pulses for nine Ivalues 102 overlap. Each pulse has 146.25 samples (e.g., three pulseshave 146 samples for every pulse that has 147 samples). For each sample,the sample of eight other I-value pulses are added to create a finalI-signal sample that is passed on to I digital-to-analog converter(IDAC) 120 at a rate of 62.4 million samples per second. Qindexed-pulse-shape-generator 118 operates similarly to Iindexed-pulse-shape-generator 116, though operating on Q values 104instead of I values 102 and creating Q-signal samples that arecommunicated to Q digital-to-analog converter (QDAC) 122.

I indexed-pulse-shape-generator 116 includes I-value buffer 314,pulse-shape lookup-table (LUT) 316, and LUT index-counter 318. I-valuebuffer 314 receives the phase-corrected gain-modified I value from gainmodifier 114. I-value buffer 314 contains the nine previously receivedphase-corrected gain-modified I values. When the phase-correctedgain-modified I value is received from gain modifier 114, Iindexed-pulse-shape-generator 116 shifts the nine previously receivedphase-corrected gain-modified I values so that the oldest I value isdiscarded from I-value buffer 314 and the phase-corrected gain-modifiedI value is shifted into I-value buffer 314. Effectively 1indexed-pulse-shape-generator 116 treats I-value buffer 314 as a queue.Pulse-shape LUT 316 contains, in this example, 1170 pulse-shapecoefficients that when multiplied by an I value will generate the firsthalf of a root-raised-cosine-shaped pulse for the I value. The firsthalf is stored since the second half is symmetrical and can be generatedby moving through pulse-shape LUT 316 in reverse order. Using thisembodiment of modulator 106 shown in FIG. 3, the amount of die areanecessary for LUT 316 is reduced by about one half.

I indexed-pulse-shape-generator 116 handles the oversampling of 16.25 byoversampling at 260 samples per value time and under-sampling by sixteensamples per value time. I indexed-pulse-shape-generator 116 initializesLUT index-counter 318 with a value of zero and increments counter 318 bysixteen. When a resulting index value is over 260 the resulting indexvalue is reduced by 260 and I-value buffer 314 is shifted to get a new Ivalue. Thus, every new I value starts with an index value of zero, four,eight, or twelve, which explains the 0.25 of the 16.25 oversample rate.Note that I values starting with an index of four, eight, or twelve willhave one less sample for that value time than those starting with anindex of zero.

At each sampling, the value in LUT index-counter 318 is used to find apulse-shape coefficient within pulse-shape LUT 316 for each of the nineI values in I-value buffer 314. Note that each of the found coefficientsare 260 increments from each other in LUT 316. For example, the indexvalues used to lookup coefficients when the value in counter 318 is zeroare: 0, 260, 520, 780, 1040, 1039, 779, 519, and 259. These index valuesassume that index values range from zero to 1209 for LUT 316. LUT 316may also be segmented into nine segments to allow for simultaneousaccess by each of nine lookup operations corresponding to each I value.The nine segments are from indices 0-129, 134-259, 260-389, 390-519,520-649, 650-779, 780-909, 910-1039, and 1040-1169. Here the timingadvance and retardation are accomplished by incrementing or decrementingcounter 318 by sixty five (¼ of 260 and thus ¼ of a value time).

Q indexed-pulse-shape-generator 118 operates similarly to Iindexed-pulse-shape-generator 116. Q indexed-pulse-shape-generator 118operates on Q values 104 instead of I values 102. Qindexed-pulse-shape-generator 118 includes a Q-value buffer 320, apulse-shape lookup-table (LUT) 322, and a LUT index-counter 324, which Qindexed-pulse-shape-generator 118 uses to generate pulse shapes for Qvalues 104 instead of I values 102.

At this point these example operations of modulator 106 are complete.Continuing this detailed example, however, converter 108, using IDAC 120and QDAC 122, receives final I-signal samples from 1indexed-pulse-shape-generator 116 and final Q-signal samples from Qindexed-pulse-shape-generator 118, respectively. IDAC 120 and QDAC 122output analog I and Q signals, also respectively.

Note that here conversion to analog is complete, though processing fortransmission can be performed, such as by transmission processor 110.Transmission processor 110 receives, at mixers 124 and 126, I and Qanalog signals, respectively. Local oscillator (LO) 128 provides afrequency signal for transmission. Quadrature circuit 130 provides aninety-degree phase shift. This phase shift causes the frequency signaloutput to mixer 124 to be ninety degrees out of phase with the frequencysignal provided to mixer 126. Mixers 124 and 126 mix the analog I and Qsignals with the frequency signals provided by quadrature circuit 130 tocreate up-converted I and Q signals. The up-converted I and Q signalsare output to combiner 132. Combiner 132 combines the up-converted I andQ signals into a transmittable signal 134. Transmittable signal 134 maybe transmitted as is or may be further modified (e.g., amplified).

Note that one or more of the entities shown in FIGS. 1 and/or 3 may befurther divided, combined, and so on. Thus, these entities illustratesome of many possibilities (alone or combined) that are capable ofemploying the described techniques.

FIG. 4 illustrates a method 400 for Improving WCDMA Modulation. Thesetechniques may include at least the method illustrated below. Aspects ofthe method may be implemented in hardware, firmware, software, or acombination thereof. The method is shown as a set of acts that specifyoperations performed by one or more entities and is not necessarilylimited to the order shown.

At 402, an I or Q value is received. The I or Q value may have beenamplified and corrected for phase distortion. At 404, a time-shiftedsample of a shaped pulse based on the I or Q value is generated. At 406,the time-shifted sample is provided to a digital-to-analog converter.

By way of example, consider application of method 400 to the operatingenvironment illustrated in FIG. 1. In this environment, modulator 106performs the operations of method 400. Modulator 106, through phasecorrector 112, receives a non-amplified non-phase-corrected I or Q value(102 or 104). Phase corrector 112 receives information from an externalsource indicating that an amplification of the non-amplifiednon-phase-corrected I or Q value will result in a phase distortion.Phase corrector 112 rotates the non-amplified non-phase-corrected I or Qvalue to correct for the phase distortion.

In some embodiments, phase corrector 112 uses a polar-to-rectangularlookup-table (LUT), such as polar-to-rectangular LUT 308 of FIG. 3, toaid in the rotation. Phase corrector 112 rotates the non-amplifiednon-phase-corrected I or Q value by a number of degrees, such as ten,and in increments of ten degrees. Ten-degree increments are not requiredbut are effective and do not require as large a lookup-table 308 assmaller-degree increments. By rotating the non-amplifiednon-phase-corrected I or Q value, phase corrector 112 creates anon-amplified phase-corrected I or Q value, which it communicates togain modifier 114.

Modulator 106, through gain modifier 114, receives the non-amplifiedphase-corrected I or Q value from phase corrector 112. Gain modifier 114determines a gain coefficient using a gain lookup-table (LUT), such asgain LUT 312 of FIG. 3. Gain modifier 114 modifies both the I and Q ofeach non-amplified phase-corrected I or Q value pair using unique gaincoefficients.

At 402, the I or Q value is received by I indexed-pulse-shape-generator116 or Q indexed-pulse-shape-generator 118, respectively. I or Qindexed-pulse-shape-generator (116 or 118) generates a time-shiftedsample of a shaped pulse based on the I or Q value (102 or 104). I or Qindexed-pulse-shape-generator (116 or 118) may use a pulse-shapelookup-table (LUT), such as pulse shape LUT 316 or 322 of FIG. 3, tooversample the I or Q value by 260 and under-sample the I or Q value(e.g., by 16). Pulse-shape LUT 316 and 322 contain pulse-shapecoefficients that I or Q indexed-pulse-shape-generator (116 or 118)multiplies with the I or Q value to generate samples that together forma shaped pulse. I or Q indexed-pulse-shape-generator (116 or 118)determines whether or not a request to advance or retard the signal hasbeen made. If such a request has been made, I or Qindexed-pulse-shape-generator (116 or 118) can modify the index used tolookup coefficients in pulse-shape LUT 316 by positive or negative 65(i.e. ¼ of 260). The next sample generated will be the time-shiftedsample generated at 404.

In some embodiments the time-shifted sample is combined with othertime-shifted samples prior to being provided to a digital-to-analogconverter at 406. I or Q indexed-pulse-shape-generator (116 or 118)combines the time-shifted sample with time-shifted samples of eightother I or Q values (102 or 104). In this example, an I or Q valuepersists in I or Q value buffers 314 or 320 for nine total value-times(the rate of repeating 402). I or Q indexed-pulse-shape-generator (116or 118) generates different parts of a pulse for each I or Q value. As Ior Q indexed-pulse-shape-generator (116 or 118) receives new I or Qvalues at 402, the oldest I or Q values are discarded. By the time I orQ indexed-pulse-shape-generator (116 or 118) has shifted an I or Q valuethrough buffers 314 or 320 a fully shaped pulse has been generated forthat I or Q value. I or Q indexed-pulse-shape-generator (116 or 118)repeats 404 and 406 at a rate that is 16.25 times faster than 402 isrepeated. At each instance of 404 a single sample of each I or Q value'sshaped pulse is generated. These single samples are combined prior to406.

At 406 I or Q indexed-pulse-shape-generator (116 or 118) provides thetime-shifted sample, possibly within a combination of samples, to Idigital-to-analog-converter (IDAC) 120 or Q digital-to-analog-converter(QDAC) 122. IDAC or QDAC (120 or 122) then converts received samplesinto an analog signal.

One or more of the techniques described above can be performed by one ormore programmable processors executing a computer program to performfunctions by operating on input data and generating output. Generally,the techniques can take the form of an entirely hardware embodiment, anentirely software embodiment, or an embodiment containing both hardwareand software components. In one implementation, the methods areimplemented in software, which includes but is not limited to firmware,resident software, microcode, etc. Furthermore, the methods can take theform of a computer program product accessible from a computer-usable orcomputer-readable medium providing program code for use by or inconnection with a computer or any instruction execution system.

For the purposes of this description, a computer-usable orcomputer-readable medium can be any apparatus that can contain, store,communicate, propagate, or transport the program for use by or inconnection with the instruction execution system, apparatus, or device.The medium can be a non-transitory electronic, magnetic, optical,electromagnetic, infrared, or semiconductor system (or apparatus ordevice) or a propagation medium. Examples of a computer-readable mediuminclude a semiconductor or solid state memory, magnetic tape, aremovable computer diskette, a random access memory (RAM), a read-onlymemory (ROM), a rigid magnetic disk and an optical disk. Currentexamples of optical disks include compact disk-read only memory(CD-ROM), compact disk-read/write (CD-R/W) and DVD.

Although the subject matter has been described in language specific tostructural features and/or methodological techniques and/or acts, it isto be understood that the subject matter defined in the appended claimsis not necessarily limited to the specific features, techniques, or actsdescribed above, including orders in which they are performed.

What is claimed is:
 1. A system comprising: a digital-to-analogconverter; a gain lookup-table; a gain modifier, the gain modifierconfigured to: receive a non-amplified phase-corrected I or Q value;determine a gain coefficient using the gain lookup-table; and modify thenon-amplified phase-corrected I or Q value by the gain coefficient toproduce gain-modified phase-corrected I or Q value; a pulse-shapelookup-table; an indexed pulse-shape-generator configured to: receivethe gain-modified phase-corrected I or Q value from the gain modifier;retrieve a pulse-shape coefficient from the pulse-shape lookup-table;create a time-shifted sample of a shaped pulse based on thegain-modified phase-corrected I or Q value and the pulse-shapecoefficient; and provide the time-shifted sample to thedigital-to-analog converter.
 2. The system as recited in claim 1,wherein the digital-to-analog converter is configured to produce ananalog signal using the time-shifted sample, the analog signal beingpart of a transmittable signal.
 3. The system as recited in claim 1,wherein: the gain modifier is further configured to increment an indexfor each pair of the non-amplified phase-corrected I or Q values, theindex used to retrieve the gain coefficient from the gain lookup-table.4. The system as recited in claim 3, further comprising: apolar-to-rectangular lookup-table; and a phase corrector, the phasecorrector configured to: receive an I or Q value; determine that anamplification of the I or Q value will result in a phase distortion;retrieve a correction I or Q value from the polar-to-rectangularlookup-table, the correction I or Q value corresponding to a rotationthat corrects the phase distortion; and create the non-amplifiedphase-corrected I or Q value using the I or Q value and the correction Ior Q value, the non-amplified phase-corrected I or Q value being arotated version of the I or Q value.
 5. The system as recited in claim4, wherein the rotation is a number of degrees divisible by ten.
 6. Thesystem as recited in claim 5, wherein the polar-to-rectangularlookup-table contains correction I or Q values for zero-degree,ten-degree, twenty-degree, thirty-degree, and forty-degree rotations. 7.The system as recited in claim 1, wherein the time-shifted sample is afirst sample, the shaped pulse is a first shaped pulse, thenon-amplified phase-corrected I or Q value is a first non-amplifiedphase-corrected I or Q value, and the indexed pulse-shape-generator isfurther configured to: combine the first sample with a second sampleprior to providing the first sample to the digital-to-analog converter,the second sample being a sample of a second shaped pulse based on asecond non-amplified phase-corrected I or Q value.
 8. The system asrecited in claim 1, wherein the pulse-shape lookup-table is segmentedinto multiple segments effective to enable a number of simultaneouslookup operations.
 9. The system as recited in claim 1, wherein theindexed pulse-shape-generator is further configured to modify an indexvalue to cause the time-shifted sample to shift in time, the index valueuseful for retrieving the pulse-shape coefficient from the pulse-shapelookup-table.
 10. The system as recited in claim 1, wherein the indexedpulse-shape-generator is configured to provide the time-shifted sampleat a first rate of repetition that is higher than a second rate ofrepetition at which the indexed pulse-shape-generator is configured toreceive gain-modified phase-corrected I or Q values.
 11. A methodcomprising: receiving a first I or Q value; generating a firsttime-shifted sample of a first shaped pulse based on the first I or Qvalue; combining the first time-shifted sample with a secondtime-shifted sample, the second time-shifted sample being a sample of asecond shaped pulse based on a second I or Q value; and providing thecombined time-shifted sample to a digital-to-analog converter.
 12. Themethod as recited in claim 11, wherein generating the first time-shiftedsample and providing the combined time-shifted sample are repeated at arate higher than receiving the I or Q value.
 13. The method as recitedin claim 11, wherein generating the first time-shifted sample isperformed using a pulse-shape lookup table.
 14. The method as recited inclaim 13, further comprising: shifting the first time-shifted sample intime by modifying an index value for retrieving a pulse-shapecoefficient from the pulse-shape lookup-table, the pulse-shapecoefficient for generating the first time-shifted sample.
 15. The methodas recited in claim 11, wherein receiving the first I or Q valuecomprises receiving a first non-amplified phase-corrected I or Q value,the method further comprising: determining a gain coefficient using again lookup-table; and modifying the first non-amplified phase-correctedI or Q value by the gain coefficient to produce the first I or Q value.16. The method as recited in claim 15, wherein receiving the first I orQ value comprises receiving a first non-amplified non-phase-corrected Ior Q value, the method further comprising: receiving the firstnon-amplified non-phase-corrected I or Q value; determining that anamplification of the first non-amplified non-phase-corrected I or Qvalue will result in a phase distortion; and rotating the firstnon-amplified non-phase-corrected I or Q value to correct the phasedistortion to produce the first non-amplified phase-corrected I or Qvalue.
 17. The method as recited in claim 16, wherein rotating the firstnon-amplified non-phase-corrected I or Q value is performed using apolar-to-rectangular lookup-table.
 18. The method as recited in claim16, wherein rotating the first non-amplified non-phase-corrected I or Qvalue rotates the first non-amplified non-phase-corrected I or Q valueby a number of degrees that is divisible by ten.
 19. A System-on-Chipcomprising: a digital-to-analog converter configured to generate analogsignals useful to transmit data; a modulator configured to: receive afirst I or Q value; generate a first time-shifted sample of a firstshaped pulse based on the first I or Q value; combine the firsttime-shifted sample with a second time-shifted sample, the secondtime-shifted sample being a sample of a second shaped pulse based on asecond I or Q value; and provide the combined time-shifted sample to thedigital-to-analog converter.
 20. The System-on-chip of claim 19, whereinthe system-on-chip is configured to generate analog signals fortransmitting data in compliance with a wideband code division multipleaccess (WCDMA) communication standard.